1Department of Applied Physics, cNM, Eindhoven University of Technology, 5600MB Eindhoven, The Netherlands.

Abstract

Apparent c(2x2) superstructures within the narrow beams of an interference pattern spreading in the 100 directions at the surface of Cu(001) are observed by scanning tunneling microscopy. These features are induced by electron scattering from Ar- and Ne-filled subsurface nanocavities. The beams originate from electron anisotropy resulting in focusing of bulk electrons. We developed a model providing a good agreement between simulations and experiments. Particularly, a simple explanation of the angular distribution for the interference pattern and the period in the superstructure is found.